The concept of a medical apparatus for humidifying or otherwise treating a gas from an insufflator during surgery is described in Douglas Ott et al. U.S. Pat. Nos. 5,411,474; 6,068,609 and 7,066,902. Briefly, an insufflation gas is heated and hydrated i.e. conditioned, before the gas is directed into a body cavity through a device such as a trocar. In order to hydrate the insufflation gas a charge of hydration fluid is typically injected into a device where the hydration fluid can humidify the insufflation gas and a heater can bring the insufflation gas to a temperature near body temperature. The conditioned insufflation gas is then sent to a trocar for injection into a body cavity of a patient.